DE2752699A1 - SOLID COLOR CAMERA - Google Patents

Description

DESCRIPTION

The present invention relates to a solid-state color camera in which, as the solid-state image sensing device, a semiconductor body, e.g. a device working with charge coupling in the form of a chip or a device of the so-called bucket chain type (bucket brigade device) or the like is used.

A solid-state color camera is already known in which a device operating with charge coupling in the form of a Chips is used, which in carriers that are generated depending on an object to be picked up after an interline transfer system operates. Such a chip in the form of a carrier transmission system usually has a vertical shift register for each of a plurality of image sensing elements which are arranged vertically one above the other. The carriers extracted from the respective vertical shift registers are supplied to a horizontal shift register through 1H, i.e., a horizontal scanning line, and the information corresponding to 1H is transmitted through the output terminal of the horizontal shift register is

give. The frequency of clock pulses P _H supplied to the horizontal shift register is usually selected to be 4.5 MHz or more. However, if you choose the frequency of the clock pulses P _H so that it corresponds to the color subcarrier frequency of the standard color television signal according to the NTSC system, it is not necessary to convert the clock frequency of the color subcarrier, so that it is possible to use a simple signal processing circuit to a To convert the output signal of the camera into a signal suitable for the NTSC system. Such an arrangement is described in the applicant's US patent application Ser. No. 794,804 on May 9, 1977. However, if the frequency of the color subcarrier is selected as the clock frequency, the problem described below occurs. In the NTSC system, as is known, the phase of the color subcarrier frequency fg returns to the initial value after every four partial images. _{If one chooses the amount T H} in the horizontal direction for the division of the image sensing elements in a chip that works with charge coupling, it can happen that, depending on the phase relationship between the image sensing elements and the color subcarrier frequency fg, a vertical shift register does not exist where there is no image sensing element Signal can be taken. Therefore, it is necessary that it, acts on the signals corresponding to the image sensing elements of the vertical shift register by signals that are obtained by shifting signals of the image sensing elements on the left and the right side of the vertical shift register by a time corresponding to 1 / 2 T " corresponds. If the signal is output in the phase regular order of the color subcarrier frequency, it is necessary for this purpose to provide a phase adjusting circuit, and therefore it is necessary to further provide a switching signal generating circuit which generates a switching signal for the phase adjustment. As a result, the whole circuit structure becomes complicated, and hence it becomes pointless to use clock signals having the same frequency as the color subcarrier.

Since the picture element in question has been shifted by 1/2 f moreover, the displacement of the image cannot be corrected even if the phase is corrected so that that you get back to the normal phase.

The invention is based on the object of a solid-state color camera to create in which the disadvantages of the color cameras known up to now are avoided.

According to the invention, this object is achieved, for example, by creating a solid-state color camera in which three chips working with charge coupling are used, the frequency of clock pulses P ^, which are fed to the horizontal shift registers of the chips, is selected so that a color signal whose The carrier has the same frequency as the color subcarrier of the standard NTSC system can be taken from the output terminals of the chips, the signals being read out in the phase sequence of the color subcarrier frequency f _g . Thus, according to the invention, it is possible to omit the signal processing circuit which has heretofore been used to convert _{the carrier frequency of a primary color signal into the color subcarrier frequency f g;} Furthermore, the phase correction is unnecessary if the color subcarrier frequency fg is selected for the carrier frequency, so that neither a phase correction circuit serving the stated purpose nor an associated driver circuit is required; therefore, there is a considerable simplification of the entire circuit structure. According to the invention, since the spatial arrangement of the image sensing elements is the same as that of the reproduced picture elements, impairment of the reproduced image is also avoided.

In the above-described known method of achieving a phase correction does not match the spatial arrangement of the picture elements with the arrangement of the picture elements

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the reproduced image because it is shifted by 1/2 ^ to the left or right, so that the quality of the reproduced image deteriorates. According to the invention, this disadvantage is avoided.

According to the invention, three chips operating with charge coupling are used, and a signal color filter is arranged in front of each chip which transmits red, green or blue light; the outputs of the three chips are combined to give the desired color video signal, the carrier frequency for each primary color being 3.58 MHz.

Is carried out at another embodiment of the invention in which only two chips or a single chip of the type mentioned, wherein the frequency of Ausgäbetaktsignale for the horizontal shift registers in two chips 2 f _g and with only one chip with 3 _s f elected it is possible to take a color signal which has the same repeating frequency as the color subcarrier according to the NTSC system, in a manner similar to the three-chip camera directly from the two chips or one chip.

Embodiments of the invention are explained in more detail below with reference to schematic drawings. It shows:

Fig. 1 shows an example of a solid-state image sensor of an interline transfer system;

2A to 2D representations to illustrate the respective Phase position of the color subcarrier signal in the NTSC system;

Fig. 3 is an illustration of the relationship between a solid-state image sensor and the phase of a color subcarrier »- frequency;

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4 is a diagram for illustrating a known signal output method;

5 shows an illustration for explaining a signal output method according to the invention;

Fig. 6 is a diagram showing the relationship between the signal output and associated electrodes;

7 is a view of part of a solid-state image sensor for use in a solid-state color camera according to the invention ;

8 to 11 each show a section along the line VIII-VIII or IX-IX or X-X or XI-XI in FIG. 7;

Figs. 12A to 12D show the waveforms of pulses for the Driving the solid-state image sensor;

13 and 14 each show a representation to illustrate the carrier displacement or displacement direction for the embodiment of FIG. 7;

Figure 15 is a view of a portion of another embodiment of a solid-state image sensor similar to that 7 for use in a solid-state color camera according to the invention;

16 shows the section XVI-XVI in FIG. 15;

17 and 18 representations to illustrate the carrier transfer or the direction of displacement in the exemplary embodiment according to FIG. 15;

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19 shows an illustration of a color filter for a camera with two chips operating with charge coupling;

Fig. 20 shows part of an embodiment of a practical usable color filter;

Fig. 21 is a block diagram showing the main part of a circuit for a solid-state color camera according to the present invention;

22A to 22F are illustrations for explaining the operation of the circuit of FIG. 21;

23 shows a part of a color filter used in an inventive Camera with only one charge-coupled chip is used;

24 shows a block diagram of a circuit for a circuit according to the invention Solid-state color camera with only one charge-coupled chip; and

FIGS. 25A to 25C, FIGS. 26A to 26C and FIG. 27 representations for explaining the mode of operation of the circuit according to FIG Fig. 24.

As mentioned, a solid-state image sensor has been created by the invention, in which at least one chip working with charge coupling is used, which is designed as a two-line transmission system for the carrier, which is generated as a function of an object to be picked up.

1 shows an embodiment of a charge coupled chip 10 in the form of an interline transfer system. According to FIG. 1, the chip 10 has a plurality of image or Image sensing elements 1, which are arranged vertically below one another and form several vertical rows. For everyone

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vertical row of image sensing elements 1, there is a single vertical shift register 2, and the various Carriers taken from vertical shift registers are fed to a horizontal shift register 3 by 1 H. Finally, the information from 1 H is output via a terminal 7. In Fig. 1 the carrier transmission or directions of displacement indicated by arrows.

The chip 10 of Fig. 1 is intended for the case that a mirror image of an object, not shown, with the help a lens, not shown, is projected onto the chip; on the other hand, a laterally correct image of the object becomes projected through the lens onto the chip 10, the chip is formed so that the image sensing elements opposite to the perpendicular Shift registers 2 are arranged reversed.

A recording or sensing clock pulse P _s , which is used to generate carriers in the corresponding image sensing elements 1, is fed to the image sensing elements via a terminal 4, while a two-phase transfer or shift pulse P .. ( P _v1 , Py ₂ ) is fed. Furthermore, the horizontal shift register 3 is fed a two-phase clock or query pulse trains via a terminal.

Up to now it has been customary to choose the value 4.5 MHz for the frequency of the clock pulses P ^ to be fed to the horizontal shift register. However, if one chooses, for example, the color subcarrier frequency f _{g of} a color television signal for the clock pulses P _H , for example according to the NTSC system, it is not necessary to convert the clock frequency, i.e. the repetition frequency of the output color signal of the chip 10 does not need to be converted into the color subcarrier frequency f _s from 3 »58 MHz, and therefore a simple structure of the signal processing circuit results.

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device for converting the output signals of the camera into signals for the NTSC system. However, the following problem arises if the frequency f _{s of} the color subcarrier is selected for the clock signals.

In the NTSC system, as is well known, a field is created in that the horizontal lines 1 H to 262.5 H are swept over, and then the horizontal lines 262.5 to 525 H are swept over and interlocked with the lines of the first field; here, the phase of the color subcarrier frequency f _{s is} reversed for each line of the same field, as shown in Figs. 2A and 2B; furthermore, a phase inversion takes place in every field of the same frame, and the phase is also reversed in each of two frames, so that the phase of the color subcarrier frequency fo returns to its original position every fourth field or field. If the phases in the first partial image according to FIG. 2C are designated with a circle and a hatched circle or a square or a hatched square is used to designate the second or the third or the fourth partial image, the result shown in FIG. 2C shown phase relationship for the color subcarrier frequency fg, where Tj ₁ corresponds to the division of the image sensor 1 in the horizontal direction. In FIG. 2C, the sequence of the repetition of certain phases in adjacent partial images is indicated by arrows, and FIG. 2D illustrates the regularity of the phase sequence.

If one chooses the distances or the division of the image sensing elements 1 in the chip 10 according to FIG. 1 in the horizontal direction according to FIG. 2C with T _H , the phase relationship shown in FIG. 3 between the image sensing elements and the color subcarrier frequency fg results. Since no signal is taken out of the vertical shift register 2, which has no image sensing elements, it is necessary, as the signal to be sent to the image sensing element

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on the vertical shift register corresponds to using a signal which is generated in that the signal of an image sensing element, which is on the left or right side of the vertical shift register, is shifted in time by the amount 1 / 2f ". In order to output the signal with the same phase as that of the color subcarrier frequency f _g , or in order to maintain the phase sequence, it is necessary for this purpose to provide a phase adjustment circuit and a switching signal generator cooperating therewith. However, this results in a complicated structure of the circuit and it is pointless to choose a frequency for the clock signals which is equal to the frequency f _{g of} the auxiliary carrier.

Even if the phase is corrected to coincide with the normal phase, the shift may cause a Image cannot be corrected, because the signal corresponding to the image sensor in question is shifted by 1/2 fu.

According to the invention, this disadvantage is overcome by the application a special signal output method avoided.

In known arrangements, the data stored in all the image sensors 1 signals are output in the direction indicated in Fig. 4 by numbers order within the period of one field as output signals of the working charge coupled device "while according to the invention for the signals in the order of the phase of the color subcarrier frequency _g of the color television signal can be output according to the NTSC system. As shown in FIG. 5, the image sensing elements from which signals are to be extracted are determined as a function of the relevant field. In Fig. 5, the numbers indicate the order of signal output in accordance with the order of the fields. In a first embodiment of the invention three chips are used, with each chip the signals

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are output in the sequence shown in FIG. 5, and color filters are assigned to the chips, by means of which Red, green and blue signals are generated.

A first embodiment of the invention is explained in more detail below. So that the signals can be output in the sequence shown in FIG. 5, the electrode assigned to each image sensing element is divided into two electrode elements, e.g. according to FIG Image sensing element group (without hatching), the signals of which are output in the third and fourth fields, and the relevant groups of elements are _{supplied in the desired manner with recording pulses or sensor clock signals Pg 1} and P ₃₂ , as explained below.

In the following, a chip 10 operating with charge coupling is described with reference to FIGS. 7 to 11, to which the signals in in the manner described above. 7 shows a view of the chip 10, while FIGS. 8 to 11 show the Sections VIII-VIII, IX-IX, X-X and XI-XI in Fig. 7 show.

In Fig. 7 one recognizes several image sensing elements S ₁ , S ₂ , S, and S ^, on which the image of an object is projected, and whose index numbers 1 to 4 each designate the relevant partial image. In the following a set or a group of image sensors is considered, which are arranged within a vertical row. Within each group, the image sensors, which correspond to the partial images 1 to 4 in the carrier transmission direction indicated by arrows, are periodically arranged in the form of a row in groups of four image sensors, and channel delimitation devices 11, shown in hatched lines, are provided between adjacent vertical rows of image sensors as shown in FIG that have such a plan shape,

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that they extend approximately over four edges of each feeler. Between the vertically extending parts of the channel delimitation devices 11 and the sensors there is an overflow outlet 12, to which a control gate G _{D is} assigned.

Each vertical row of image sensor groups is assigned a vertical shift register 2 which is actuated by two-phase transmission or shift pulses Py ₁ and P _v p; According to FIG. 7, electrodes fi _v1 and φγ2 are present for the two phases. To determine the direction of the carrier transfer, the electrodes ^ _v1 and ^ _v2 are formed according to FIG. 9 so that the thickness of an insulating layer 14, which is on a substrate of SiO ₂ or the like. located on the top 13a of a semiconductor substrate 13 is changed so that there is a change in the depth of the potential shown in Fig. 9 with a solid line, and that under the insulating layer 14 of small thickness, a potential barrier and a potential well 15a arise. In Fig. 7, so-called storage electrodes ^ y | (s) ¹ ^ ^ V2 (S) are arranged on the thin parts of the insulating layer 14. Furthermore, so-called transmission electrodes and corresponding to the thick parts of the insulating layer 14

A transmission gate jL is arranged between each image sensor 1 and the associated storage electrodes serves to transfer the carrier of the sensor in question to the associated potential well 15a according to FIG. 9; however make up the transmission gates are constituent parts of said storage electrodes, and according to FIG. 8 only the silicon dioxide layer 14 has a different thickness in this area.

According to the invention, the electrode ^ ₅ , which is assigned to each sensor in order to supply it with the recording or sensing pulse.

lead, divided into two electrodes ^ ₃₁ and ^ ₃₂ , which according to FIG. 6, the desired sensing clock pulses P ₃₁ and P _{32 are} fed. The image sensors S ₁ and S ₂ , which are used in the first and second partial image, are _{assigned the first electrode 0 31 in} common, and correspondingly the image sensors S 1 and S ^ for the third and fourth partial image are assigned the second electrode 0 _S2 assigned together. These two electrodes have such a shape that they cover the areas of the associated image sensor and the gate G _{D of} the overflow drains 12. In the present case, the electrodes ^ ₃₁ and ^ _{32 are} transparent, and the chip 10 is optically shielded with the exception of the areas occupied by the image sensors S ₁ -S ^.

In the present case it is assumed that when the voltage which is applied to the electrodes ^ ₃ and φ »of the chip 10 changes from the value 1 to the value 0, the potential well 15a in the chip assumes a smaller depth. The image sensors 1 and the vertical shift registers 2 are supplied with the pulses shown in FIGS. 12A-12D. The sensor clock pulse P ₃ , which is fed to the first electrode ^ ₃ V and the second electrode ^ ₃₂ , consists similarly to known arrangements of a memory _{pulse P sc} »by means of which the carrier is generated, which corresponds to the light information of the object, and an im The following pulse P _ST », which is a control pulse and serves to transfer the carrier to the vertical shift register 2, and whose unit period corresponds to four fields.

The first sensor clock pulse P ₃₁ , which is supplied to the first electrode φ ^ , contains the control pulse P _ST within each vertical blanking period V.BLK of the first and second fields, as shown in Fig. 12A, during that supplied to _{the second electrodes ^ 32} The second sensor clock pulse P _{32 contains} the control pulse P _3T in the third and fourth fields, as shown in FIG. 12B.

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The first vertical shift clock pulse P _v1 and the second vertical shift clock pulse Py ₂ *, the latter _{corresponding to Py 1} , which are fed to the first electrode ^ y ₁ and the second electrode ^ y _{2 of} each vertical shift register 2, are shown in FIG. 12C and 12D by pulses whose phases are opposite to each other in each field.

In the following it will be explained with reference to FIGS. 8 and 9 in which way the signals are taken from the chip 10 with the aid of the pulses described above. The extraction of the signal for the first field is described as an example, which corresponds to the period indicated by IV in FIG. Since the potential indicated by a solid line in FIG. 8 is present within the storage period which corresponds essentially to a perpendicular period of the potential in the chip 10, carriers corresponding to the image of the object are generated in the image sensors. In the present case, the support in the vertical shift register 2, the values 1 and 0 take place within the carrier accumulation period for transmitting the vertical shift pulses Py ₁ and Py ₂ alternately to, but is in Fig. Simplicity 8 only the potential well under the electrode ^ y ₁ as Shown having a shallow depth. The carriers of the image sensors S ₁ and S ₂ , to which the first sensor clock pulse P _{g1 is} supplied, are transferred to the vertical shift register 2 during the transfer period following the storage period. Since the vertical shift clock pulses Py ₁ and Py ₂ », which are in phase opposition, are _{fed to the electrodes ^ y 1} and ^ y _{2 of} the vertical shift register 2, and since their phase relationship is selected, for example, according to FIGS. 12C and 12D, the potential relationship between the Vertical shift clock pulses Py ₁ and Py ₂ during a period P, during which ^ y _{1 has} the value 1 and ^ _{31 has} the value 0, so that only the potential well under the electrode φ ^ becomes deeper, during

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the potential well under the electrode ^ g ₁ assumes a smaller depth. In other words, in the vertical shift register 2 results in a potential relationship as is indicated in Fig. 9 by dashed lines, so that only the carrier C from the image sensor S ₁ of transmitted over the gate # _G to the vertical shift register 2. Thus, the carriers generated in the sensor Sp are even not transmitted, when the potential at which assumes the value 0 the sensors S ^ and S ^ ₂ together associated electrode _s1.

After the transmission period has elapsed, the vertical shift register 2 is _{supplied with the vertical shift clock pulses P v1} and Py ₂ as shown in FIGS. 12C and 12D within the period 1H, so that during this period the carriers from the vertical shift register 2 into the horizontal shift register 3 according to FIG. 1 are transferred.

Fig. 0 illustrates the transfer of the carriers from the sensor S ^ to the vertical shift register 2. In Fig. 8, the potential indicated by dashed lines, which corresponds to the depth of the potential well, shows that the carriers C are output when ^ ₃₁ has the value 0 and ^ _{v1 has} the value 1. Fig. 10 shows that the lines for supplying the clock signals to the electrodes φ ^ and ^ _v2 are arranged on the channel delimitation devices; 9 shows that the transfer of the carriers in the vertical shift register 2 is carried out in the vertical direction, the broken line representing the potential indicating that the carriers are transferred when ^ _v1 is 0 and ^ " ₂ is 1 has; 11, the image sensors S ^ - S ^ are isolated from one another by the channel delimitation device.

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The carriers fed in parallel to the horizontal shift register 3 are output one after the other with the aid of a sensor, clock pulses P _{H being} fed to the horizontal shift register. As mentioned, when using three chips 10 for the colors red, green and blue, clock pulses are supplied which have the same frequency fg as the color subcarrier, this frequency being 3.58 MHz in the present case.

Since the shift _{clock pulses Py 1} and Py _{2 are} in phase opposition at intervals of 1V, only the potential under the electrode jiy ₂ is made even lower by the other shift _{clock pulse Py 2 when the second partial image arrives.} As a result, only the carriers from the sensor S _{2 are transferred} to the vertical shift register 2 and then to the horizontal shift register 3 corresponding to the interval 1H and then output one after another. Fig. 13 shows the direction of carrier transfer for the first two fields. In Fig. 13, the solid arrows denote the transfer of the carriers for the first field, while the dashed arrows denote the transfer of the carriers in the second field.

Correspondingly, in the case of the last two fields, by combining the second sensor clock pulse P ₃₂ with the shift _{clock pulses Py 1} and Py _2, the carriers for each field are output from sensors S and S ^ in the corresponding order. 14 illustrates the transmission of the carriers in the last two fields.

If the carriers or signals are output with the aid of the clock pulses described, it is possible to output the signals with a phase which is equal to the phase of the color subcarrier frequency f _g . For example, if you use three chips working with charge coupling and place monochrome filters in front of them,

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which transmit red or green or blue light, and when you combine the output signals of the chips, you get the desired color video signal at which the carrier frequency of all primary color signals is 3.58 MHz.

If three chips are used in the manner described above, the color subcarrier frequency f _{s of} the NTSC system is selected for the frequency of the clock pulses P "to be fed to the horizontal shift registers 3, and the signals are output in the phase sequence of the color subcarrier frequency. According to the invention, it is therefore possible to omit the signal processing circuit which has been used up to now, by means of which the carrier frequency of the primary color signals is converted into the color subcarrier frequency fg * and therefore the phase correction which is necessary when the carrier frequency is converted into the color subcarrier frequency f _g is unnecessary. Thus, the use of a phase correction circuit and the circuit for driving the phase correction circuit are unnecessary, so that a considerably simpler circuit structure results according to the invention.

Furthermore, the spatial arrangement of the image sensors is the same as that of the reproduced picture elements, so that the quality of the reproduced image is not impaired. In the known method for phase correction, the spatial arrangement of the sensors does not coincide with that of the reproduced picture elements, and because of the phase correction, the picture elements are shifted to the left or right by 1/2 _Η · This shift leads to an impairment in the known arrangement the quality of the reproduced image.

In the embodiment described above, chips operating with charge coupling are used, in which each vertical row of image sensors has a vertical sliding part 0 9 8? 6/0 5 6 7

register is assigned. However, the invention can also be applied to a chip in which a vertical shift register is assigned, for example, to two vertical rows of image sensors. Such a chip is referred to below as a modified chip. 15 shows such a modified chip 10, in which a vertical shift register 2 is assigned to two rows of image sensors on the left and right sides, respectively, with several such sets lying horizontally next to one another and the overflow drains 12 being arranged between adjacent sets. In Fig. 15, the hatched areas indicate the channel delimitation devices described above. Since the signals from the sensors in the relevant partial images are output in a similar manner as in the embodiment described above, the wiring of the electrodes is of the same type as in the arrangement described with reference to FIG. The relationships between the potentials of the clock pulses which are fed to the electrodes φ ^ , Φ§2 * ^ V1 ¹ ^ ^ V2 ^and the image sensors to be scanned are shown in the table below in conjunction with FIG. 15.

time Sensor clock signal * S2 V register
signal Clock Output 1. Partial image * S1 1 * V1 * V2 sensor 2. Partial image O 1 O 1 Sensor 1 3. Partial image O O 1 O Probe 2 4. Partial image 1 O O 1 Probe 3 1 1 O Probe 4

FIG. 16 shows the section XVI-XVI of the modified chip 10 according to FIG. 15, which corresponds to FIG. 8 and the potential relationships the clock pulses illustrates the electrodes during the storage period corresponding to the solid lines and during

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the transfer or deferral period corresponding to the dashed line in the first sub-image.

The modified chip 10 is also grounded in FIG. 12 clock pulses shown supplied.

For the modified chip 10 are the signal and carrier transmission directions in the various partial images in FIGS. 17 and 18 shown similarly to the one above described embodiment.

If the modified chip 10 is used, and if the frequency f _{g of the color subcarrier is selected as the frequency of the clock pulses P H} to be fed to the horizontal shift register 3, the signals being output with the same phase as the color subcarrier frequency, the same effect can be achieved achieve as in the embodiment described above. In the modified chip 10, the area occupied by two sensors in the horizontal direction corresponds to two thirds of the corresponding area in the known charge-coupled chip, so that the device or the camera according to the invention has a compact structure, at the same time a better image resolution results.

In the further figures, further exemplary embodiments of the invention are shown in which one or two chips are used to produce the desired color video signal.

First, an embodiment with two chips will be described. In the case of a color video signal E _Q according to the NTSC system, the carrier color signal is expressed by the color subcarrier which is modulated by the color difference signals (RY) and (BY) so that it is used when generating a color video signal with the aid of two chips working with charge coupling to simplify the Signal processing is desirable that

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the color difference signals as output signals from the camera Chips can be removed on direct V / ege.

The color filters and circuit arrangements used for this purpose are described below. The filter for obtaining the color difference signal from R will first be discussed. Since there is a phase difference of 180 ° between the color information R and Y, an imaginary color filter 20, shown in FIG. 19, which corresponds to the signal output conditions according to FIG. 5, must be used. If you combine two sensors in the horizontal scanning direction to form a dividing unit and choose the light separation properties so that the information R and Y are alternately obtained, the filter elements for the first and second partial image allow colored light to pass through, as shown in the upper part of Fig 19 is shown. In the third field, the phase of the color subcarrier frequency f _{g is} opposite to the phase in the first field, and accordingly the second and fourth fields have opposite phases. Thus, the light separation properties of the third and fourth fields are opposite to those of the first and second fields, and therefore the filter elements of the third and fourth fields transmit colored light as shown in the lower part of FIG.

When it is impossible to manufacture a filter so that a unit area of the filter is that of the area of an image sensor corresponds, with a certain partial image the colored light R, but with another partial image lets the colored light Y through, i.e. that one and the same unit area of the filter transmits two different types of colored light it is impossible to use a sensor as shown in FIG. 19 for the R signal in the first field and the Y signal in the third field refer to.

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Therefore, according to the invention, the colored light that the corresponds to the first and the second partial image, corresponding to the light separating properties of the filter 20 with those in the upper part of Fig. 19 is selected, and in the third and fourth fields, the output signals are checked before they are used vice versa. It is thus possible to obtain the same output signals as in the case of the imaginary filter 20 according to FIG Fig. 19.

In the embodiment mentioned, a mosaic-shaped filter 20A according to FIG. 20 is therefore used. A comparison of Fig. 20 with Fig. 19 shows that the filter 20A has the same light separating properties as are obtained by scanning the upper row of sensors of Fig. 19 for the first and second fields and for the third and fourth Field electrically reverses the output signals 1R, 1Y, 1R, 1Y, 2Y, 2R, 2Y, 2R etc. Similarly, the color difference signal from B can be obtained with the aid of a color filter 20B which allows colored light rays B and Y to pass through. Since, as is well known, in the color signal according to the NTSC system there is a phase difference of 90 ° between the color difference signals of R and B, for practical use, for example, the filter 20B is offset from the filter 20A according to FIG 1/2 _H. Instead of moving the two filters against each other, however, the signals can be influenced electrically, for example with the aid of a delay line.

FIG. 21 shows an exemplary embodiment of a circuit in which the two filters 20A and 20B according to FIG. 20 are used. The image of an object 0 is generated on the chips 1OA and 1OB with the aid of an objective L and the filters 2OA and 2OB. The two chips are supplied via terminals 6 with clock pulses P _H , the frequency of which is twice as high as the frequency f _{s of} the color light carrier, so that according to FIG

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the information taken from the sensors corresponds to half the division of the sensors. Interrogation and hold circuits 21A and 21B, which are connected to the outputs of the chips 10A and 10B, are supplied _{with the same clock pulses Pp 1 as drive pulses.} The interrogation signal or the clock pulse P ^ which is supplied to the interrogation and hold circuits 21A and 21B is shown in FIG. 22D. Sensed dot sequence signals S and S of the chips 10A and 10B are supplied through the sample and hold circuits to signal processing circuits 22A and 22B each of which has a gamma correction circuit and so on; from there the signals pass to brightness and color difference signal processing circuits 23, 24A and 24B.

The circuit 23 for processing the luminance signal Y will now be described. The respective recorded output _{signals S A} and S "consist of the signal components shown in FIGS. 22A and 22B, and the aforesaid signals which pass through the processing circuits 22A and 22B are _{supplied to a switch SW 1} which is activated by the switching signal shown in FIG. 22E S .. is controlled with the switching frequency 2f _g , so that the composite signal S _c shown in Fig. 22C is obtained. The signal S _c is fed to an interrogation and hold circuit 25, which is controlled by the interrogation _{signal Sy according to FIG. 22F, the atirage frequency f g being} used. In this way, the brightness components Y1 and Yt, which originate from the chip 10A and the chip 10B, are taken from the composite signal S ^ and are then fed to a low-pass filter 26 from which a brightness signal is taken which is composed of components exists, which have a low frequency of, for example, 1 to 2 MHz.

From the switch SW ₁ , the composite signal S _{c is} also fed to a low-pass filter 27, as shown in FIG.

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filters 26. The output signal of the low-pass filter 27 and the signal S _c are both fed to a subtraction circuit 28 which generates a signal which contains only the high-frequency components of the composite signal Sp, which include the primary color components of R and B, whereupon the signal is a Admixer 29 is fed, which is also fed with the low-frequency component from the low-pass filter 26. The mixer 29 therefore generates a composite brightness signal Y, the low-frequency component of which consists of the real brightness _{signals Y R} and Y _β , and the high-frequency component of which is formed by the high-frequency component of the composite signal S _c. According to FIG. 21, a delay line 30 is provided, by means of which the delay caused by the low-pass filter 27 is compensated.

Since the processing circuits 24Λ and 24B for the R and B color difference signals are similar, only the circuit 24A will be described below. 21, the color difference signal (RY) processing circuit 24A includes a bandpass amplifier 31A, a phase inverter 32A and a switch SW ₂ which is operated every 2V. Since the sideband components with the clock frequency f _s as the center frequency are used as the color difference signal of R, the bandwidth of the bandpass amplifier 31A is chosen so that it also includes the clock frequency f _s . Since it is sufficient that the reverse output signals in the third and fourth fields are used as color difference signals, as was described with reference to FIG. 19, the switch SW _{2 is switched over} in the third and fourth fields, as shown in FIG Lines is indicated so that the color difference signal (RY) can be taken from this switch.

The color difference signal (B-Y) can be taken out in a similar manner from a switch SW, which is connected to the other signal processing circuit 24b heard.

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a?

The thus obtained color difference signals (RY) and (BY) and the luminance signal Y to a color encoder 33 are shown in FIG 21 supplied to the the desired color video signal S _n at its output terminal. 34 - can appear ^.

Fig. 23 and the other figures show an embodiment of the invention for generating the color video signal Sj ^^ using a single charge-coupled chip. In Fig. 23, the color filter 20 is shown as an example, which is used in the embodiment described above. This color filter has vertical Stripes for the colors red, green and blue. The order of signal output is the same as above described.

FIG. 24 shows an embodiment of a color camera according to the invention in which the color filter 20 according to FIG. 23 is used. Although the circuit 23 for processing the luminance signal Y is basically constructed in the same way as that of the circuit of FIG. 21, the low-frequency components of the luminance signal Y are obtained in the manner described below. In the present case, the primary color signals are not matrixed, but the brightness signal for the NTSC system can be obtained directly from each of the primary color signals from R, G and B, which result from the point following system. In view of this, a control or gate circuit 40 is connected upstream of the low-pass filter 26. A recorded or sensed signal S _D shown in FIG. 25A is supplied to the circuit 40 from the chip 10 via the interrogation and hold circuit 21.

The signal S _{1 of} FIG. 25B for controlling the circuit 40 is a pulse signal which is synchronized with the clock pulses Pu supplied to the chip 10, the frequency being the same but different

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the pulse widths corresponding to the primary color signals to be controlled differentiate. In other words, the level Εγ of the brightness signal Y according to the NTSC system is expressed in a known manner by the following equation:

E _Y = 0.30 E _R + 0.59 E _G + 0.11 E _ß (1)

Here, E ~, E "and E _ß denote the levels of the primary color signals for R, G and D. If the levels of the associated controlled output signals are to correspond to equation (1), it is therefore sufficient if the pulse widths" *, "* and _B1 which correspond to the associated primary color signals R, G and B are selected so that they satisfy the conditions of the following equation as shown in FIG. 25B:

R Β _ B

Π73Ο " ⁼ o75?" Π7ΤΤ (2)

Thus, the control circuit 40 generates a controlled output signal P _{G1 of} FIG. 25C in the form of a pulse width modulated signal, so that when the controlled output signal P _{G1 is passed} through the low-pass filter 26, it is possible to obtain a low component in which the the same level relationship exists as in the case of the brightness signal according to the NTSC system. According to FIG. 24, a pulse shaper 41 is provided for generating the pulse signal S ₁ . Thus, in the signal processing circuit described above, it is not necessary to provide a circuit which causes the respective primary color signals to appear simultaneously, and there is also no need for a matrix circuit by means of which the brightness system for the NTSC system is obtained.

At the processing circuit 24 for the color difference signals of R and B can be similar to the brightness signal be worked according to the pulse width modulation method.

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For this purpose, according to FIG. 24, a control circuit 44 and a control signal shaper 45 are provided. The control signal shaper 45 supplies a control signal S ₂ with the pulse widths Top, "Cn? And t ^ p" which are selected according to FIG. 26B so that they correspond to the following equation and control the associated primary color signals R, G and B.

B2 ^C G2

If a pulse which controls the primary color signal of R is chosen as the phase center point, for a phase difference OjvD between this pulse and a pulse for controlling the primary color signal of B and for a phase difference O _RG between said pulse and one controlling the primary color signal of G Pulse does not use the values 120 ° and 240 °, but the phase angles are determined as follows:

⁰ RB * ¹¹⁶ ' ⁵ °

Ö _RG = 222.9 ° (4)

If the relationship between the primary color signal R and the burst signal is selected as shown in FIG. 27, and the controlled output signal P ^ g of FIG. 26C is supplied from the control circuit 44 from a bandpass amplifier 31, the output signal E _{c is obtained} according to the following calculation:

E _c = K {0.63 R cos (co _s t + 13.5 °) + 0.45 B cos (U> _s t + 13.5 - 116.5 °) + 0.59 G

cos (^ _s t + 13.5 ° - 222.9 °)}

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Here, K denotes a constant and tü _ß the angular frequency of the clock pulses P ^.

If the pulse-width-modulated controlled output signal P _G 2 is fed to the bandpass amplifier 31, the color carrier signal S "according to the NTSC system can be taken directly from the circuit.

When using the method described above, it is therefore not necessary to use a signal processing circuit provide in which the sideband components with the in their Middle-lying clock frequency detected and then fed to the encoder v / ground in order to generate a color carrier signal modulated to ground.

The brightness signal Y and the color carrier signal S _c are fed to an admixer 47 after they have been generated in order to be combined with the synchronization signals (VD, HD, the color sync signal, etc.) of a pulse generator 35, which then generates the color video signal according to the NTSC system.

As described above, according to the invention, the signals are made according to the phase of the color subcarrier frequency fg of the NTSC system to complete the task at hand and there is no limit to the number of charge coupled devices used in the camera working chips. Furthermore, according to the invention, it is possible to use chips of the type with hidden channels.

According to the above description, the clock pulses P ^ are chosen so that the repetition frequency of _{the color signals removed from a chip is equal to the frequency f s of} the color subcarrier for the NTSC system. If three chips are used for the three primary colors, then f _H = f _g applies. Delivers a single chip according to

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Fig. 24 shows the primary color signals of R, G void B, ^P H ⁼ ^ ^f S »" ¹ ^ ^{when the} color difference signals (RY) and (BY) are generated by two chips, as shown in Fig. 21, P holds _H = 2 f,

¹ S *

Although the above description applies to embodiments of the invention in which the generated color signal is the NTSC system, but it should be noted that the invention can also be used when following with a color signal the PAL system is used.

In the described exemplary embodiments of the invention, chips operating with charge coupling are used as solid-state image sensors is used, but it would also be possible to use other charge transfer chips, e.g. bucket chain type, charge injection devices and solid state devices of the MOS type.

teivbanwalt:

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Claims (1)

PATENT CLAIMS Solid-state color camera with
an image sensor in which several image sensing elements are aligned both horizontally and vertically, a storage register for image information sensed by the image sensing elements, an output register for outputting the stored image information, an output terminal that sends the image signal through the output register is fed, as well a filter arrangement for generating predetermined colored images on the various image sensing elements, characterized by an electrode arrangement for reproducing a color image signal from the image sensing elements in such a way that a sequence of signal scanning and a predetermined color subcarrier phase order of a standard color television signal is maintained, as well as by a device for supplying a clock carrier signal (P ^) to the output register (3) »where the clock carrier signal is selected so that the output signal at the output terminal (7) has a predetermined color subcarrier frequency equal to that of the standard color television signal. 809826/0562 2. Solid-state color camera according to claim 1, characterized in that said storage register is a vertical one Shift register (2), which is arranged parallel to the vertical direction of the image sensor (1), and by means of whose the charge signals which are transmitted by the image sensor represent sensed image information, to the output register (3) by the electrode array supplied Clock signal (p ") are transmitted. 3. Solid-state color camera according to claim 2, characterized in that the vertical shift register (2) is used as required to transmit the image information that is _{felt on both sides of the image sensing elements (S 1} - S ^). 4. Solid-state color camera according to claim 2, characterized in that four image sensing elements of the image sensor too are combined in a unit from which the selected image information is transferred to the vertical shift register (2) the image information of the predetermined subcarrier phase order of the standard color television signal correspond. 5. Solid-state color camera according to claim 1, characterized in that the image sensor includes three chips (10) with image generation devices which operate with charge transfer, that the filter arrangement for three primary colors is arranged in the beam path of each of the image generation devices, and that output signals of the image generation devices are mixed to obtain the color image signal. 6. solid-state color camera according to claim 5, characterized in that it is in the working charge transfer chip by working with charge-coupled chips. 7. Solid-state color camera with an image sensor, which includes a first and a second chip, which have charge transfer image forming devices, which include a plurality of image sensing elements which are aligned both horizontally and perpendicularly to one another, a storage register for storing by the image sensing elements sensed image information, an output register for outputting the stored image information, an output terminal to which the image signal is fed from the output register, as well as several color filter elements which correspond to the image sensing elements, the filter elements having radiation permeability values such that they successively contain first primary color information and first brightness signal information in the case of the first chip operating with charge transfer and a second primary color information item as well as second luminance signal information one after the other in the case of the second chip operating with charge transfer du rch Lassen, gekennzei c'h'-het by an electrode arrangement for reproducing a color image signal from the image sensing elements of the image generating devices operating with charge coupling in such a way that an interleaved signal scanning sequence and a predetermined color subcarrier phase sequence corresponding to a standard color television signal is maintained, as well as by a device for Supplying a clock pulse carrier signal to the output register (3), the carrier signal being selected so that the output signal at the output terminal (7) has a predetermined color subcarrier frequency which is equal to that of the standard color television signal . .- · ■■. - ,. ■ :. ...: · ■. · ■■: ■. - ^: - ·. ■ - ■ ■ ·. 0. Solid color camera according to claim 7, characterized in that that the filter elements are arranged to be in the first charge transfer chip successive horizontal rows let through first color and brightness signal information in antiphase, and that on the second chip, with successive horizontal - ⁴ - 275269? Arrange the second color and luminance signal information let through, wherein of the first and second color and brightness signal information that the first and the second chip are removed, one is selected for the purpose of obtaining said standard color television signal. 9. Solid-state color camera according to claim 8, characterized by a circuit arrangement by means of which the first and second color and brightness signal information, the taken from the first and second charge transfer chips, respectively, at each vertical field interval be reversed in phase so that the same number of filter elements each of said numbers of image sensing elements are shared in each vertical sub-image. 10. Solid-state color camera according to claim 7, characterized in that that the charge transfer chips are charge-coupled chips.